Cosmic Endgame: 4 Years
by Austin.Imaginativ3
Summary: The End is Nigh. The Beginning is Here. A Queen has made her Wish. Prismo is obliged to answer, and has followed it, including bringing Finn the Human to Prismo's Lair. Finn will Hear Her Out, and he will decide the Fate of Three Worlds. If he listens to the End, the most Terrible Secret that Finn Wants to Know will be Revealed. How much can Four Years Change a World? AU-Story
1. Cast List

_Author's Note: Currently the Cast List for the Story, For my Benefit More than Yours. Please Leave Reviews and Comments as well as suggestions, as they fuel my Imagination Zone for more ideas. Theories always appreciated. _

_**Important:** The Majority of the Cast list, except **The Unknown** , are meant to be read as leading into one another, if this confuses some people at first.  
_

 ** _Prismo Begins:_**

This story is great, long, and very tall. Take a whiff of adventure with your bud by reading this story, make sure you taking your rocking Axe along, keep your Hat on at all times, and your sword always by your side. Join Finn and Jake in their most out of this universe (literally) adventure. Meet the cast of this new story.

 **The Found: (Our Players)**

Fionna the Human, the hero of the story and who's best friend is

Cake the Cat, who hates her old owner Simone and the (slightly evil)

Marshal Lee the Vampire King, Secret Crush of Simone, Best Friend of

Prince Gumball, the first crush of Simone, best friend to

Lord Monochromicorn, Lord of the Monochromicorns, and relative of

Lady Ranicorn, Exile and Friend of

Princess 'Bonnie' Bubblegum sister of the prince, and daughter to

Queen Bubblegum, Mother figure of

Simone the Ice Queen, Daughter of

Simon the King of Haven, friend of

Flame Prince, Secret Love of Fionna and brother to

Flame Princess, the Princess of Water, 2nd best BFF of Fionna, and former apprentice of

Martin the Hero, Legend, The Father of Fionna

 **The Lost Causes: (The Side Story)**

Jake the Dog, Thief and Magical Misfit, Player of Viola whose home to

Shelby the Worm, Conscience for Jake in times of need, his Advisor, and Enemy of

Tiffany, Freeloading thief and False friend

 **The Plain Lost: (On a Banana Boat?)**

Fionna's Mother, Black Haired Beauty, former Wife of Martin, lost to an unknown party,

presumed to be The Cosmic King

 **The Monsters: (Our Antagonists)**

The Lich Queen, Monster that ended the World 998 Years ago

 **The Unknown: (The Secrets This New World Holds)**

The Mysterious Grassland Thief King, a Grass Elemental, former Thief, and owner of Fiona's Tree house. The Grassland King, a man who no one has ever seen, he asks for nothing from the tenants of his kingdom, save a meager portion of food every day, left outside the tree house by night, and gone by morning.

The Cosmic King, an entity of unknown intention, who only appeared after the Death of Martin the Hero, his story is shrouded in secret, only in that Martin was the only one who knew the King's true plans.

Glob, A Martian Man who keeps watch over Mars in the absence of it's King, Lincoln, alternate titles: Grob, Gob, and Grod; he watches over Earth as the new world of Ooo takes it place. It is said his Wife went into self exile centuries ago to the planet below for unknown reasons, Glob unable to stop her as his duties kept him unable to leave.

 **The Storyteller: (The Scribe Who Writes This Fantastic Tale Down)**

Prismo, cosmic entity located outside of time, once dead, now alive again through Finn and Jake's help, his subconscious being Old Man Jake. Breaker of Fourth Walls, King of Dreams and Wishes, Cosmic Entity and Best Buds with the Cosmic Owl.

 **The Center of Attention: (Our Possible Protagonist/Antagonist)**

Finn the Human, Hero? He doesn't know it yet, but World's are about to collide, Gods, Monsters, and Men will tear his reality apart, and Finn will find out the biggest secret he has always wanted to know may not be worth it.

The Cosmic Queen, Villian? She knew the consequence of Her wish, but she chose it anyway at the cost of her power. She has a goal, an Endgame to this wish, but no one but her would ever know it, except the one she wished to know, Finn the Human. Her game could render this new dream either a smoking ash, or a beautiful new world.

 **The Consequence of this Game: (Reality Ripping Apart)**

The potential Death of **Both** Realities, Two Mirrors, as They are Reborn into a new One.

 **OOO**

-or-

 **AAA**

Only one will survive...

But will it be a better World?

Maybe.

We

Will

See

Won't

We

 **?**


	2. The Proposition

**Author's Note: Here's the first chapter to my little story. Updates will definitely be random, but I'll try to do it every two weeks or so. Flame's appreciated, constructive critiscism also,** **tell me if I have any errors and I'd love to fix them. Also, Name has been changed to Four Years, due to relevance as the story progress** **es.**

 **I do not own Adventure Time, but if I did, I'd keep Finn x Flame Princess.**

 _Chapter 1: The Proposition_

The sunset was beautiful, full of pinks and reds, like Pheeb's hair when she got wet, or got embarrassed. I might be a dense glob of meat, but I think my emotions have become a lot clearer since I accepted my 'Vault' as a part of me. Emotions suck, I probably should have taken that Comet's offer and given up my meat-bag of a body. Maybe it was just another day of fruitless search talking, but, ya know, whatevs'.

"Hey Dude!" Jake calls from the bottom of the tree. He uses his stretchy power to end up right next to me at my perch at the top of the Tree Fort. "Man, I know you're bummed out and all, but I need you to focus on the bright side," he says, "You're alive and all that junk, with all the stuff we've faced in the past three months looking across all of Ooo, we should be happy we survived, I mean, we barely survived the Wasteland again after the Goo Creature's tried to attack us in Bubblegum's machine." He stretched his arm down towards the window, grabbing a tub of Ice Cream from the fridge, pulling it back up along with a pair of spoons. "Well, I'm off with the Ice Cream to Ladies', spending the night there Bro," Jake says, quickly turning into his giant form and walking towards his Wife's house.

"Jake, you suck at this, bro," I say sighing, before looking next to me to see a small bowl of Ice Cream, a Spoon, and a note which read 'I Don't Suck' on it. I give it a sad smile, before I dig into it and watch the last of the sun's rays going down.

 _The Next Morning_

I awoke after another random dream about a world full of pillows, before I get up to make myself breakfast, while BMO goes about doing his 'thing', whatever it was today. Slinging my sword, I start to make my way to the Candy Kingdom and PB's lab, but decided to take a turn to the forest instead, deciding to go scope out a new dungeon to raid later.

* * *

Walking into the deep, dark, unexplored part left in the Forest, he stumbles across the remains of an old rotted out tree of proportions much like his own Tree Fort, including what appeared to be the remains of a similar fort to his own. Wanting to look at the spot at a later date, he leaves a marker he knew wouldn't be disturbed. Suddenly he hears something from behind him. Turning he sees nothing but shadows and empty air, but he can't shake the feeling of being watched.

Gigging and laughing then exploded through the silence, sounding from all around the spot Finn is at, and he sees one of the shadows move outward and toward another clearing. Quickly following, he runs after it.

* * *

 _(Finn's PoV)_

The insane laughing was beginning to bug me, and the shadow, a woman from what I could see of the dress, or perhaps robe, was all I could catch before my foot snagged on a root and I went tumbling down, hard. Instead of finding dirt and rock though, I went face first into a swirling portal.

* * *

 _Prismo's Room_

 _Outside Time and Space_

Feeling his surroundings, he noticed he was in a pile of pillows, and cracking his eyes open, he saw Prismo being cast on the wall across from him. "Hey, hey Finn, I can tell you are awake," he then tells the Human, "I'm sorry I had to bring you here like this, but unless I did what she asked, she would have killed me again, bro." At that, Finn finally realized the bed containing Prismo/Jake was placed below a giant sword floating in the air. Next to it was a woman with hair that looked like it was full of stars that reached to her stomach, with a midnight blue cloak that concealed her body and left her face in shadow, not showing any part of her face but the midnight black hair that flowed out the opening. Chuckling with an icy, echoing voice, the woman in question quickly took the sword in her hand, seemingly shrinking the sword to a more normal size.

"Why the heck did you bring me here lady?" Finn asks quickly, assuming a battle stance, and with nothing to wield, his sword seemingly gone from his side, his arm draws forth his Sword of Grass. Giggling again, she motions, and the Blade of Grass withers and dies.

"My, my, such temper for a young adult and hero such as yourself," she says, "Then again your world isn't known for being peaceable at this point in time, is it..." Trailing off the woman turns to Prismo. "You know our deal Prismo, tell him the Bargain, the conditions of my game, let him know what my wish was," she says, smirking beneath her shadowy face, "I have a lot to prepare for now..." Moving her hand in a motion, another portal opens, and she steps through it, leaving Prismo and Finn alone.

"Dude...what the heck is going on Prismo?" Finn asks the Wish Master, and Prismo looks nervous. Materializing a chair, Prismo tells Finn to sit.

"I'm sorry Finn, but I can't really tell you much about who she was except that she is known as the Cosmic Queen, a cosmic entity that travels through the Multiverse at large playing games with inhabitants of different dimensions, and I don't mean Parcheesi," Prismo continues, "It's said she has an endgame that connects all of the varying realities, that she is searching for something or someone lost to her in her original timeline." He materializes a jar of pickles and offers one to Finn. He chose to decline.

"Ok Primo, tell me what the heck she was talking about when she was leaving," Finn demands from his pink friend. Prismo visibly saddens at this, looks downcast, and then sighs.

"Ok Finn, she has a proposition for you," he says, "She has made a wish, she has changed reality itself, it's a new world out there if you were to return to it, and she wants you to see this new world and be its judge, jury, and possibly executioner, if you see fit to it." At this, a screen is shown across the room on another wall, of another Earth from space, though this time it was whole and not missing a chunk of the world. "She has traveled the Multiverse, and in her own views, has found a way to make the Earth survive the Catalyst Comet, push back the destruction a few years so the inhabitants of the world could prepare for the oncoming disaster." He sighs, and looks to the screen, pointing toward it.

From where Finn was seeing of the universe being played before him, he saw a blue Comet come towards the Earth, and then Finn realized this was the beginning of it all. The Catalyst Comet shown on the screen was the one that would become him, that would eventually become Finn the Human. Watching the Comet approach the Earth, he couldn't help but feel sorry for the world that was about to die and be reborn into the eventual world that came before Ooo.

A beam of pure white lashed out from the surface of the Earth, striking the Comet, causing it to be pushed back, further, further, until it had begun to leave the Planet's Orbit, the screen panning to follow the Comet as it then passes Mars, before settling into orbit around Jupiter, destroying and fragmenting the planet's natural moons into smaller spheres. It then pans back down to Earth, through the atmosphere, as the Beam ends, showing a good sized fragment of the Comet still is in orbit, and escaping destruction by whatever force tried to protect the planet, and it begins plummeting to the ground below.

Now showing a view from the surface, a blue skinned man with bird feet, reminiscent of the Ice King, and adorned with a Crown much like the Ice King's, collapsed to his knee's, unable to stand or protect the world after the expenditure of energy that kept the main body of the Comet from destroying and forever altering the planet. Behind him, a dino boy watches near his poppa's side, looking to the man who he idolized, as he realizes his master can do nothing but accept the comet's collision course. Struck with courage, the Dino boy takes the crown from his slumped master's head, and donning it, is instantly morphed into a new creature, turning more humanoid, retaining his scaly visage, and gaining a tinge of color more like a greenish blue.

Raising his hands, the creature used the same white power to move the comet, only to suddenly be struck in the side by another giant creature of stone, causing the first creature to miss the comet, the fragment, though was no longer a threat, enough of it was destroyed, though still heading for the castle of Ice. Unable to stop it from impacting with the Ice tower in time, or out run it, after freezing the giant, stone creature, he encases the old man that looks like Ice King and himself in a dome of Ice, along with the stone creature. And then there was nothing but a blue flash.

Finn had to nearly shield his eyes from the blast, and the screen nearly went white, but color began to fade back in, revealing nothing but a charred crater, which was quickly filling in from the melted Ice castle, though a single, mountainous island remained in the center, the ice barrier cracking and caving in to reveal an otherwise unharmed pair of wizards and an unconscious stone dog golem. Then the ground shook under them, the island began to crack, starting from underneath the stone giant, and spreading outwards. The Ice King figure took the lizard boy in his arms, made some gestures, and using his magic, took the child to the mainland. The last frame of the show, Finn saw the lake glow a brilliant blue, before settling on a lone dark shadow under the new waves.

Fading to the white of Prismo's room, Finn finally registered that whatever he was being shown was over for now. "Prismo, what the junk was that?" he asks the Wish Master.

"Exactly what it looked like Finn, the far past of your planet," Prismo replies, "A very, very long time ago by the standards of your planet's growth, but it was not the original event, it was changed by the Cosmic Queen." Moving his hand, he replays the last few moments of the event as it naturally occurred in Finn's own timeline, as well as showing the differences in not only the people involved and the circumstances, but that the Catalyst Comet itself was changed. In the original timeline, a Green Catalyst Comet, who would become the Lich by Finn's time, was replaced with the Blue Comet that was once Finn as well. "There were consequence's though Finn, in the way this new timeline handled the end of their world, their world was preserved for four years, but only four years," Prismo says, "I'd like to show you what happened next, but for now, I'll have to show you the start of altered future by your time."

Finn nodded, and he and Prismo once more turned to the wall that served as a viewing screen.


	3. Theme Song!

**_Author's Note:_** _ **I don't Own Adventure time. Disclaimed. Also the song lyrics of the beginning are in Italics this chapter.**_

Prismo stands in the room, so to speak, with me next to him. "So, now what Prismo?" I ask the Wish Master.

"Now Finn, we show you the future of your altered world," the Wish Master says pointing back to the wall, "And it all starts with a song, much like the one you and Jake made." I stare at the wall, the room darkens, and it is as if a movie is playing on the screen.

 _(Music)_

 _Scene: A forest of barren, leafless trees, merely branches of the dead and dying plants hanging onto stumps and the weapons left from ages long gone. A figure in a green cloak, covered by shadow, a pale, human hand is seen tucking a long strand of blonde back into the hood, before fleeing into the forest with a Crown with grey gems in hand, it gleams in the sun. A Crow caws in the distance. It pans back towards a snow covered hill, before showing white capped mountains. A blue bolt reminiscent of a bolt of lightning saps past the camera, as a flying blue skinned Queen, recognized as the Ice Queen laughs malevolently._

 _Panning further it passes by the Lemongrab Castle, showing a yellow haired, light yellow skinned girl in a lemon dress looking wistfully towards a kingdom on a far hill. Turning away, she returns sadly to the Earl and Countess Lemongrabs, where she stares at a picture of her older brother, Lemonhope, on a wall of portraits._

 _Panning inward the hill is revealed to house the glorious Candy Kingdom, passing it's candy citizens going into a Circus, where a Chocolate Bar Strongman showed his strength, Gumdrop kids played merrily in the games booths, a Candycorn Clown marveled the candy citizens with his feats that defied reality, before panning to the main streets of the Candy Kingdom._

 _Candy citizens laughed and partied, before a bubblegum girl, the young Princess 'Bonnie' Bubblegum, is shown riding on Lady Rainicorn. Looking to the skies as a shadow passes overhead, the girl notices her older brother, revealed to be Prince Gumball on Lord Monochromicorn, who waves in return._

 _The Camera Pans to a Cat and a Blonde Girl who High-Five. A boom is heard._

 _Adventure Time,_

 _C'mon grab your friends,_

 _We'll go to very_

 _distant lands._

 _With_ _Cake the Cat_

 _and_ _Fionna the Human,_

 _The fun will never_ _end,_

 _it's Adventure_ _Time!_

Finn: Dude, this, is like, a total rip off of Ice King's fan fiction about us dude, don't tell me the girl is in love with him here as well!

Prismo: Dude, if you're just going to interrupt, have a sandwich and be quiet. Like I said, this is a parallel history that has replaced your world, but supplemented with characters from Ice King's freakish fan fiction and other worlds, to make it the perfect future the Cosmic Queen wanted.

Finn: *Mpphmppphhhhmmmm*

Prismo: Don't talk with your mouth full dude, it's impolite. Now I'm going to go back to the story...

Fionna woke up in her sleeping bag, with her sister Cake staring intently into her from above her face. She puffs a wisp of blonde hair out of her face, before getting up and getting ready for today's adventure. "What do you want Cake?" Fionna asks. The Cat merely smiles a Cheshire grin, before giggling and going downstairs to start breakfast. "Great, I have a mad cat for a sister, I can only hope I survive whatever she has planned," she says, putting her signature bunny eared hat on, and brushing her hair into its iconic curl. Making her way to the kitchen table, Fionna find's Cakes blueberry Pancakes, a rare breakfast treat the cat made, though she appreciated every bite with the rich syrup from the Candy Kingdom. Cake then slid up from under the table, still wearing the girl, her slit eyes making the experience even more creepy for Fionna.

"Girl, do you not know what today is?" she asks in a serious tone, her ears flattening, telling Fionna she was being serious.

"I seriously, do not know what is going on, except these yummy pancakes being digested," she replies honestly. Suddenly the Cheshire grin is back on Cake's face.

"Now now dear, I'm surrrre you remember what today is..." she purrs, "Martin the Hero is coming back from the remains of the Fire Kingdom tody, which means today is..." She trails off, but Fionna's stomach immediately drops, realizing in dread and horror what today would mean.

"Higggghhh Schoooool..." Fionna utters in pure venom, as ice suddenly climbs up her veins and deadens her limbs. Face planting into her delicious breakfast, Fionna slowly chews her food without the gusto she once had, the sweet blueberries turning sour, the syrup seemed to become to thick to swallow, and the pancakes became tough and hard to chew, not the fluffiness of a cloud they once were. "Whhhhhyyyyy?" she whines pitifully to Cake, the cat merely gives a serene pat on the head to the young heroine.

"Because your father wants you to have a good education, and we both know he can handle any threat that comes his way," the Cat replies, "That was the deal, you could be a hero while he was off exploring the vastness of the Kingdoms, but when he came home, he and Canyon would protect the outlying kingdoms, while you go to school, for however long it was." She stretches to knock on Fionna's forehead. "Besides we don't want this brain to go to w-aste," she says, her voice singsong-ing, "Besides, boys love girls with brawn, And Brains." She's teasing, but Fionna still blushes at her sister's insinuations, before she goes to get her backpack.

"F-fine, but if anything goes to south, like the Ice Queen attacks and Dad is occupied," she says, "I won't hesitate to knock someone on their butts." Now determined and steely, Fionna and Cake leave their Tree Fort, Fionna grabbing her nearest sword and slipping it in her backpack, before hopping onto a now enormous Cake, who begins walking to the Candy Kingdom.

* * *

 _(Outskirts of the former Fire Kingdom)_

A giant Motorcycle, cobbled together from scrap and working parts from ancient planes, ships, and cars, rode two figures through the rocky and only slightly volcanic plain. One wore a gauntlet with an eye, a gauntlet that had helped them get out of more situations then he could count, and a tunic of plain brown over metal armor on the chest, arms, and knees. The other wore a full suit of cryonic armor to keep her body temperature low enough to not disintegrate in this heat, and held a pair of binoculars that could scan the area ahead and around them for obstacles or monsters in their path.

"Canyon, do you have any visual on why the Fire Kingdom is dying," the man, who sported a full beard on top of a balding head, asked his companion. She shook her head, though she knew her compatriot couldn't see while driving the monster of a motorcycle.

"Not yet, but the eye in the sky hasn't come across any cold spikes since the last quake," she replies, "You know we could always ignite the volcanoes again with one of their 'Gods'." She says this sarcastically, though her older companions silence started to worry her. "You aren't...I mean, there is no way we could successfully do that without reducing the whole place into a lava bed, you know that right?" she starts, " Not even the Fire Kingdom inhabitants could survive pure lava..." Her companion was silent for a moment.

"I know, I know, we couldn't do that..." he sighs, though it is barely heard in this wind, "It looks like we'll have to return to the Queen and report what we have found so far..." Revving the engine, the two make their short journey back to the Candy Kingdom.

Arriving at the gates of the Kingdom as Fionna disembarks, the giant motorcycle comes to a stop suddenly, both riders hopping off. Running to the riders, Fionna tackles the heavyset looking, yet muscled old man. Cake to joins in the dog pile, as both hug the now laughing old man, who removes his helmet, revealing the balding dome of Martin Mertins, aka Martin the Hero.

Removing her own transparent, now unnecessary helmet and armor, Fionna's bff comes over and takes Fionna and hauls her off the grass, before doing the same with Martin. "Canyon!" she says, hugging her blue bff, squishing her in the embrace.

"Don't call me Canyon, Fi," the Water Elemental says, "Just because your dad saved me in a canyon, doesn't mean he keeps getting to call me Canyon as a nickname, its Pheobe, or Pheebs, but you know I prefer Flame Princess still as my official title." Laughing at her friends chiding, the group walks through the sugary gates, past the Banana Guards, and down the main street.

* * *

 _The Candy Castle Entrance_

"Sorry Kiddo, this is where me and Canyon have to stop," the older man says ruffling Fionna's hair through her bunny-ear hat, "I'll meet you back at your tree fort afterwards though, 'kay?" Waving as they split apart, Fionna and Cake continue on past the castle to the school at the back of the grounds, while Martin and Flame Princess continue, after FP stomps on Martin's shoes. "Ouch, I'm only Kidding F.P., you know I only use it as an endearing term," he says, rubbing the back of his head. Still simmering, her hair almost bubbling in anger, Phoebe sighs and follows the man inside.

After climbing a very tall tower, both Martin and Phoebe stop in front of a pair of double doors, after, of course, passing the room and lab of Prince Bubblegum, and the room of the Princess Bonnie. "Kid, I got to leave you here, I need you to make sure no one disturbs my chat with her highness," Martin says, "Be good." With that he slips inside, Phoebe left with her thoughts. After a minute, Martin was back outside, where he was showing confusion. "Kid, did you see the Queen somewhere else when we came in, or the Prince or Princess?" Martin asks. Shaking her head, Martin leaves down to the main hall where the Royal Family met in times of urgency, on the opposite side of the living quarters of the Castle, Phoebe quickly following.

Finding a pacing Prince Gumball, and a depressed looking Princess Bonnie, both Martin and Phoebe are instantly worried. While Martin talked with the Prince, Phoebe decided to comfort Bonnie. "Hey Bonbon, what's up," she asks the gummy princess, "Where's your mom, the big shot, at?" Instantly sniffling, she clams up, and Phoebe realizes it was the wrong thing to say.

"She left," Prince Gumball says to Martin and Phoebe, "Se left a note with no destination, but that she had business to do elsewhere, entrusting the kingdom to me in her absence, and she left shortly after she had sent you into the Flame Kingdom..." With grim realization, both Martin and Phoebe thought that they had been sent on a wild two-headed Goose chase. "Now what?" Prince Gumball asks hollowly.

Martin steels up at this. "Now, kid, you lead your people," he says, slapping the Prince on the back, "And you'll have your sister and I to help." Smiling slightly, both Prince Gumball and Princess Bonnie take heart to that, and Prince Gumball decides to make an announcement.

"We need to tell the people, not enough to freak them out," Prince Gumball says, "But enough to paint a picture of security, for now though, let's get our story straight."

* * *

 _Prismo's Time Room_

The wall fades to white again, Prismo and Finn both munching on a giant bowl of popcorn. "Now what?" Finn asks between bites of the snack. Prismo creates a holographic map of Earth, which focuses and expands before landing on the Candy Kingdom, and then focusing on a Vault.

"Now we get to the side story," Prismo says.


End file.
